This study reports new three-dimensional (3D) micromachined magnetic tweezers consisting of micro-electromagnets and a ring-trap structure, fabricated using MEMS (micro-electro-mechanical systems) technology, for manipulating a single 2 nm diameter DNA molecule. The new apparatus uses magnetic forces to exert over 20 pN with less heating, allowing the extension of the DNA molecule over its whole contour length to investigate its entropic and elastic regions. To improve the localized DNA immobilization efficiency, a novel ring-trapper structure was used to handle the vertical movement of magnetic beads which were adhered to the DNA molecules. One extremity of the DNA molecule, which was bound to the thiol-modified magnetic bead, could be immobilized covalently on a gold surface. The other extremity, which was bound to another unmodified magnetic bead, could be manipulated under a magnetic field generated by micro-electromagnets. The important elastic modulus of DNA has been explored to be 453 pN at a low ionic strength. This result reveals that DNA becomes more susceptible to elastic elongation at a low ionic strength due to electrostatic repulsion. The force-extension curve for DNA molecules is found to be consistent with theoretical models. In addition to a single DNA stretching, this study also successfully demonstrates the stretching of two parallel DNA molecules.

Recently, energy saving is one of the important issues for polymer processing industry. Electromagnetic induction heating has many advantages such as fast heating and low energy consumption. Previous studies using electromagnetic induction heating for rapid tool heating have indicated that the temperature uniformity on a cavity surface is not easy to be achieved. In this paper, two different coils were used for heating uniform 7 mm thick hot work tool steel (JIS SKD61) surface. One is a four-row coil with opposite current directions and the other is a two-row coil with identical current directions. Magnetic flux concentrators were used to control magnetic field and heat the workpiece uniformly. The heating experiment results showed that coil with opposite adjacent current directions had more uniform temperature distribution on tool surface. The temperature uniformity was about 94%∼95%. The coil with identical adjacent current directions had higher average temperature and the temperature rose from 50 ∘ C to 150 ∘ C in 15 seconds.

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A two-plunger-type dilatometer was designed and fabricated to measure cure-induced volume changes of epoxy molding compound (EMC). The device is suitable for studying volume change of material systems that are fast reacting and with high conversions and high viscosity like commercial EMC. In this paper, the conversion rate was determined by DSC. Interactions of volume change, pressure, temperature, and conversion were measured. In the experiment, two different temperatures: 172°C,180°C and four different pressures: 30, 50, 80, and 100kgf/cm2 were applied. The total number of conditions in this experiment is 8. Volume change of EMC due to thermal expansion, cure shrinkage, and thermal contraction under fixed temperature and pressure was measured. For higher pressure, the final volume change will be higher.

This study reports a new microfluidic system integrated with a microfluidic control module and a micro electrochemical module for detection of urinary proteins. The integrated microsystem can automatically detect proteins in urine with a high sensitivity. The microfluidic control module consists of a new two-way, spiral-shape micropump which can transport the urine samples to the sensing regions. The net ionic charges of the protein samples can be detected while the samples flow through the sensing region of the micro electrochemical module. Two major urinary proteins including lysozyme and albumin are detected in a multiple-channel layout with little human intervention and are analyzed in a short period of time, while only consuming a 100-mul urine sample. The developed microfluidic system could lead to a convenient, yet crucial, platform for chemical and biological detection and diagnosis.